1. Field of the Invention
The present invention relates to a pattern shape evaluation method of inspecting a pattern formed on a photomask or wafer by using an image obtained by photographing a semiconductor device and design data of the semiconductor device, a pattern shape evaluation device, and a semiconductor inspection system using the method and device.
2. Description of the Related Art
In recent years, there have been situations where manufacture of semiconductor devices is difficult because of miniaturization and multilayering thereof have been progressed and because logic thereof has been more complicated. As a result, there has been a tendency that defects to be attributed to manufacturing processes occur frequently, and it has been important to detect detects efficiently and accurately and identify problems of manufacturing processes.
The defects to be attributed to manufacturing processes include a deformed pattern, a broken pattern, a shorted pattern and the like, and these defects can be detected through comparison with a standard pattern having an ideal shape. More specifically, an operator selects a pattern having an ideal shape from patterns formed on a photomask or wafer, and the selected pattern is photographed to visualize it (i.e., to use it as a standard image). Next, a pattern of an inspection object is photographed, positions of the inspection object image pattern and standard image pattern are adjusted and a difference calculation is performed. If the inspection object image pattern contains a defect, luminance information on a defect position becomes different from that of the standard image at a corresponding position, and a difference amount becomes large. By using this phenomenon, a position having a difference value not smaller than a predetermined value is detected as a defect position.
With this inspection approach, however, since an operator is required to perform a registration work for the standard pattern, there arises a problem that the standard pattern registration work takes a long time if patterns of various shapes are to be inspected. To solve this problem, it has been tried to shorten an inspection time by automating the registration work by detecting a defect through comparison between a design pattern and an inspection pattern by using as the standard pattern the design pattern of a semiconductor device. Detecting a defect through comparison between a design pattern and an inspection pattern is disclosed in Japanese Patent Publication 2001-338304. The Publication discloses the contents that design data is changed to a shape estimated to be actually formed in an inspection object pattern, this shape is photographed, edges of the design data and an inspection object pattern are correlated to each other if a direction and an inter-edge distance of edges of the inspection object pattern existing along a normal direction of each edge of the design pattern are in a predetermined range, and edges of the inspection design pattern not correlated to those of the design pattern are detected as defects.